One would think that the term used to refer to the depth of a river or stream would be just that, depth. For some reason however the term gage (a variant of the word gauge) had been used by the U.S. Geological Survey since 1889, if not well before. There are a number of ways to measure stream gage and I’m sure many of us have seen the huge ruler that oftentimes runs up a bridge support. This tool is used to measure stream height, or gage, and is correctly called a Gage Staff. I tell you this because, after twelve hours in the car on Saturday, we felt the urgent need of a walk yesterday afternoon. Our peregrinations took us along the creek and under one of the steel truss bridges which span it. The ten foot measure on the gage staff shown below was old but recently repainted onto the component stones of one of the supporting piers. The complete gage staff measured seven to twenty feed. Although stream gage can’t tell us how rapidly water may be flowing, it can give some indication of the volume of water which is contained by the stream. Because stream contours are flattish at the bottom and slope to each bank, the volume of water held by the stream will increase as the gage increases. If you think about gage and contour together you will know that a stream at gage level 4 will hold more than twice the volume of water than a stream at gage level 2, for example. In any case I thought this old gage staff, stained with rust from the decking above, made for a nice post.

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